When a user performs printing using an image forming apparatus, an image forming apparatus requested of the printing sometimes can not perform the printing due to a mechanical malfunction, toner empty, paper jam or the like. In such cases, the user can request the printing to another image forming apparatus, and the image forming apparatus requested of the printing at first can request another image forming apparatus as a substitution of the printing.
For example, an image forming apparatus disclosed in PATENT LITERATURE #1 includes a detachable and attachable operation panel in order to perform substitution printing. When a user requests this image forming apparatus of the printing and can not perform the printing in this image forming apparatus due to some malfunction, the user detaches the operation panel from this image forming apparatus, and walks around to seek an image forming apparatus that can perform substitution printing with the operation panel.
Using wireless communication, this operation panel searches for an image forming apparatus that performs substitution printing. The operation panel keeps print data, a printing condition and the like in the operation panel, and displays a candidate of an image forming apparatus suitable to the substitution printing on the operation panel. Among the displayed candidates, a user selects an image forming apparatus that the user causes to perform the substitution printing, and the user attaches the operation panel to the selected image forming apparatus. The image forming apparatus to which the operation panel is attached performs the substitution printing.
Further, the technique disclosed in PATENT LITERATURE #1 displays a difference between a function of the image forming apparatus requested by a user of the printing at first and a function of an image forming apparatus for the substitution printing and thereby makes it easy to select an image forming apparatus that a user causes to perform the substitution printing. Here the difference of the functions is, for example, that an image forming apparatus has a finisher function such as punching and stapling but another image forming apparatus does not have it.
Furthermore, when a trouble occurs in an image forming apparatus, the technique disclosed in PATENT LITERATURE #2 uses a substitution image forming apparatus for printing maintenance information for fixing the trouble. In this technique, some substitution image forming apparatuses are registered in advance with priority levels; and when the image forming apparatus in which a trouble occurs can not print the maintenance information, it is tried to print the maintenance information using the substitution image forming apparatus selected in the order of the priority levels. The image forming apparatus in which a trouble occurs and the substitution image forming apparatus performs communication via a network with each other and thereby performs such process.
Meanwhile, recently, in order to properly carry out information management, image forming apparatuses are getting to have a user authentication function for a higher security level of information printed in image forming apparatuses. In user authentication in an image forming apparatus, an administrator registers in advance a user in an authentication server that connects to a network, and the user can use the image forming apparatus by using an authentication ID issued by the authentication server.
The authentication server is sometimes configured as an independent computer or sometimes configured to be built in an image forming apparatus as an image forming apparatus that has a user authentication function.
This authentication function prevents improper use of the image forming apparatus and leakage of printed information.